Sedmera David
Department of Cell Biology and Anatomy, Medical University of South Carolina, 173 Ashley Avenue, BSB 603, Charleston, SC 29425, USA.
Eur J Cardiothorac Surg. 2005 Oct;28(4):526-8. doi: 10.1016/j.ejcts.2005.07.001.
The arrangement of myocytes within the ventricle is critical for its contractile performance, as evidenced by significant functional impairment seen in cardiomyopathies associated with myofiber disarray or post-infarction remodeling. A review on this topic by Anderson and associates provides anatomical insight gained from a multitude of approaches, and concludes that the best concept is that of syncytial continuum with supporting collagenous matrix. The overall arrangement is in the form of several intertwined helices, and the authors find no support for a recently suggested ventricular myocardial band hypothesis. This commentary aims at providing a developmental and physiological perspective on this purely anatomical concept. Unlike some other organ systems, the developing heart has to function since very early stages to support the oxygen and nutrition demands of the growing embryo, thus putting some constraints on heart development. The ventricular myocardial architecture transforms from a single-layered tube through trabeculated stages into a mature form that relies on a multi-layered compact zone. The first evidence of helical patterns is found in trabeculated hearts during ventricular contraction, and layers with different helix pitch develop during later fetal stages as the compact zone thickens. The second major point determining ventricular contraction is the sequence of its electrical activation. The ventricular activation sequence changes concomitantly with its morphology, from slow peristaltoid through base-to-apex pattern found in looped trabeculated hearts, to mature apex-to-base direction. Thus, adult ventricular myocardial architecture is best understood when one also considers the way it developed together with its electrical activation sequence and contraction pattern.
心肌细胞在心室中的排列对其收缩性能至关重要，这在与肌纤维紊乱或心肌梗死后重塑相关的心肌病中出现的明显功能障碍中得到了证明。安德森及其同事对该主题的综述提供了从多种方法中获得的解剖学见解，并得出结论，最佳概念是具有支持性胶原基质的合胞体连续体。整体排列呈几个相互交织的螺旋形式，作者没有找到支持最近提出的心室心肌带假说的证据。本评论旨在从发育和生理学角度对这个纯粹的解剖学概念进行探讨。与其他一些器官系统不同，发育中的心脏从很早阶段就必须发挥功能，以满足不断生长的胚胎对氧气和营养的需求，从而对心脏发育施加了一些限制。心室心肌结构从单层管通过小梁阶段转变为依赖多层致密区的成熟形式。螺旋模式的第一个证据在心室收缩期间的小梁心脏中被发现，随着致密区增厚，具有不同螺旋间距的层在胎儿后期发育形成。决定心室收缩的第二个要点是其电激活顺序。心室激活顺序与其形态同时发生变化，从缓慢的蠕动样模式，到在环状小梁心脏中发现的从基部到心尖的模式，再到成熟的从心尖到基部的方向。因此，当人们同时考虑成人心室心肌结构的发育方式及其电激活顺序和收缩模式时，才能最好地理解它。
